1. Field of the Invention
The present invention relates to a system for automatically recovering the entirety of the excavated material which is retrieved during a plug removal or drilling operation, more particularly, during reverse circulation drilling using a double piping system.
2. Description of the Prior Art
Methods of bringing plugs of predetermined length to the surface have long been known but the removal of the plugs is often slowed down by the difficulty with which the plug is raised to the surface. One of the least costly methods consists in using compressed air as the drawing means and in retrieving all of the excavated material and drillings by means of separating apparatuses such a cyclones. However, this retrieval method destroys the order in which the excavated material is delivered according to the particular drilling level which has been reached and, furthermore, it has the disadvantage of requiring costly equipment.